Several suggestions exist in the prior art for depositing a layer of silicon by plasma spraying to form silicon semiconductor circuits including silicon solar cells. Solar cells formed by plasma spraying have the advantage that they do not need to be as perfect as monocrystalline silicon used for forming integrated circuits. Plasma spraying allows the formation of solar cells on nearly arbitrary substrates, such as graphite, as described by Chu in U.S. Pat. No. 4,077,818. Nonetheless, plasma spraying of semiconductor circuits, even solar cells, has never achieved widespread acceptance although operable sprayed solar cells have been reported.